Bug 1011540 - Implement Mul Recover Instruction. r=nbp

js/src/jit-test/tests/ion/dce-with-rinstructions.js

@@ -192,6 +192,35 @@ function rsub_object(i) {
     return i;
 }
 
+var uceFault_mul_number = eval(uneval(uceFault).replace('uceFault', 'uceFault_mul_number'));
+function rmul_number(i) {
+    var x = 2 * i;
+    if (uceFault_mul_number(i) || uceFault_mul_number(i))
+        assertEq(x, 198  /* = 1 * 99 */);
+    return i;
+}
+
+var uceFault_mul_float = eval(uneval(uceFault).replace('uceFault', 'uceFault_mul_float'));
+function rmul_float(i) {
+    var t = Math.fround(1/3);
+    var fi = Math.fround(i);
+    var x = Math.fround(Math.fround(Math.fround(Math.fround(t * fi) * t) * fi) * t);
+    if (uceFault_mul_float(i) || uceFault_mul_float(i))
+        assertEq(x, 363); /* != 363.0000324547301 (when computed with double multiplications) */
+    return i;
+}
+
+var uceFault_mul_object = eval(uneval(uceFault).replace('uceFault', 'uceFault_mul_object'));
+function rmul_object(i) {
+    var t = i;
+    var o = { valueOf: function () { return t; } };
+    var x = o * i; /* computed with t == i, not 1000 */
+    t = 1000;
+    if (uceFault_mul_object(i) || uceFault_mul_object(i))
+        assertEq(x, 9801);
+    return i;
+}
+
 var uceFault_mod_number = eval(uneval(uceFault).replace('uceFault', 'uceFault_mod_number'));
 function rmod_number(i) {
     var x = i % 98;
@@ -231,6 +260,9 @@ for (i = 0; i < 100; i++) {
     rsub_number(i);
     rsub_float(i);
     rsub_object(i);
+    rmul_number(i);
+    rmul_float(i);
+    rmul_object(i);
     rmod_number(i);
     rmod_object(i);
 }

js/src/jit/MIR.h

@@ -4343,7 +4343,7 @@ class MSub : public MBinaryArithInstruction
 
     bool writeRecoverData(CompactBufferWriter &writer) const;
     bool canRecoverOnBailout() const {
-        return specialization_ != MIRType_None;
+        return specialization_ < MIRType_Object;
     }
 };
 
@@ -4440,6 +4440,11 @@ class MMul : public MBinaryArithInstruction
     TruncateKind operandTruncateKind(size_t index) const;
 
     Mode mode() const { return mode_; }
+
+    bool writeRecoverData(CompactBufferWriter &writer) const;
+    bool canRecoverOnBailout() const {
+        return specialization_ < MIRType_Object;
+    }
 };
 
 class MDiv : public MBinaryArithInstruction

js/src/jit/Recover.cpp

@@ -364,6 +364,38 @@ RSub::recover(JSContext *cx, SnapshotIterator &iter) const
     return true;
 }
 
+bool
+MMul::writeRecoverData(CompactBufferWriter &writer) const
+{
+    MOZ_ASSERT(canRecoverOnBailout());
+    writer.writeUnsigned(uint32_t(RInstruction::Recover_Mul));
+    writer.writeByte(specialization_ == MIRType_Float32);
+    return true;
+}
+
+RMul::RMul(CompactBufferReader &reader)
+{
+    isFloatOperation_ = reader.readByte();
+}
+
+bool
+RMul::recover(JSContext *cx, SnapshotIterator &iter) const
+{
+    RootedValue lhs(cx, iter.read());
+    RootedValue rhs(cx, iter.read());
+    RootedValue result(cx);
+
+    if (!js::MulValues(cx, &lhs, &rhs, &result))
+        return false;
+
+    // MIRType_Float32 is a specialization embedding the fact that the result is
+    // rounded to a Float32.
+    if (isFloatOperation_ && !RoundFloat32(cx, result, &result))
+        return false;
+
+    iter.storeInstructionResult(result);
+    return true;
+}
 
 bool
 MMod::writeRecoverData(CompactBufferWriter &writer) const

js/src/jit/Recover.h

@@ -26,6 +26,7 @@ namespace jit {
     _(Ursh)                                     \
     _(Add)                                      \
     _(Sub)                                      \
+    _(Mul)                                      \
     _(Mod)                                      \
     _(NewObject)                                \
     _(NewDerivedTypedObject)
@@ -210,6 +211,21 @@ class RMod MOZ_FINAL : public RInstruction
     bool recover(JSContext *cx, SnapshotIterator &iter) const;
 };
 
+class RMul MOZ_FINAL : public RInstruction
+{
+  private:
+    bool isFloatOperation_;
+
+  public:
+    RINSTRUCTION_HEADER_(Mul)
+
+    virtual uint32_t numOperands() const {
+        return 2;
+    }
+
+    bool recover(JSContext *cx, SnapshotIterator &iter) const;
+};
+
 class RNewObject MOZ_FINAL : public RInstruction
 {
   private: